Writing about random topics

Genetics has shaped my personality

Over the past couple of years, I’ve been reading a lot about genetics and its influence on personality. When I was in university, I took a class on Sociology. The basis of the class was that personality was heavily influenced by culture. Furthermore, one of the major paradigms of humanity is “the blank slate” – the idea that humans are (nearly) infinitely malleable. This was a reaction to the eugenics movement of the first half of the 20th century that stated that some people just had superior genes.

However, “the blank slate” is wrong. While culture and environment shape us, we are not infinitely malleable. We are are not even greatly malleable. It turns out that our genetics, just as it shapes our physical bodies, also shapes our personalities. We can do things to affect it and choose to behave in certain ways, but our brain structures and genes dictate greatly how we react internally, and then we choose to override it.

One of those personality traits is introversion. I’ve been introverted as far back as I can remember, with the possible exception of when I was less than 5 years old. But it turns out that introversion is probably genetic. Dr. Jerome Kagan has been studying the introversion/extroversion phenomenon and has tons of data.

I found this one excerpt:

For example, he believes, based on his data, that high reactivity is associated with physical traits such as blue eyes, allergies, and hay fever, and that high-reactive (introverted) men are more likely than others to have a thin body with a narrow face.

Um:

I have blue eyes

I have hay fever (although no other allergies – although I do get nosebleeds easily in dry weather)

I have a thin body

My face is narrow

In other words, the description 100% describes me!

I thought that was eerie. I used to think that I was in control of my own personality and that I could change it with enough work. That’s not really true; I can change it to some extent but I have much less free will than I thought.